Perhaps you should try some spelling variations:
vien cay » vien cac, vien xay, vien can
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
vien cao » vien cac, vien dai, vien da
vu sach » vu bach, vu khach
ty nang » ky nang, ty xang, ty hang
su sach » so sach
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) OR (su sach)) ty nang x hoi. hieu ((vien cay) or (vien cao)) thuc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (su sach)) ty nang x hoi. hieu ((vien cay) OR (vien cao)) thuc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (su sach)) ty nang x hoi. hieu ((vien cay) or (vien cao)) thuc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (su sach)) ty nang x hoi. hieu ((vien cay) or (vien cao)) thuc van hanh vi cua tre*.